NTFS: Fix a stupid bug in __ntfs_bitmap_set_bits_in_run() which caused the

      count to become negative and hence we had a wild memset() scribbling
      all over the system's ram.

Signed-off-by: Anton Altaparmakov <aia21@cantab.net>

2 files changed, 6 insertions, 2 deletions

diff --git a/fs/ntfs/ChangeLog b/fs/ntfs/ChangeLog
index 83f3322765cd..de58579a1d0e 100644
--- a/fs/ntfs/ChangeLog
+++ b/fs/ntfs/ChangeLog
@@ -102,6 +102,9 @@ ToDo/Notes:
           inode instead of a vfs inode as parameter.
         - Fix the definition of the CHKD ntfs record magic.  It had an off by
           two error causing it to be CHKB instead of CHKD.
+        - Fix a stupid bug in __ntfs_bitmap_set_bits_in_run() which caused the
+          count to become negative and hence we had a wild memset() scribbling
+          all over the system's ram.
 
 2.1.23 - Implement extension of resident files and make writing safe as well as
          many bug fixes, cleanups, and enhancements...
diff --git a/fs/ntfs/bitmap.c b/fs/ntfs/bitmap.c
index 12cf2e30c7dd..7a190cdc60e2 100644
--- a/fs/ntfs/bitmap.c
+++ b/fs/ntfs/bitmap.c
@@ -1,7 +1,7 @@
 /*
  * bitmap.c - NTFS kernel bitmap handling.  Part of the Linux-NTFS project.
  *
- * Copyright (c) 2004 Anton Altaparmakov
+ * Copyright (c) 2004-2005 Anton Altaparmakov
  *
  * This program/include file is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as published
@@ -90,7 +90,8 @@ int __ntfs_bitmap_set_bits_in_run(struct inode *vi, const s64 start_bit,
         /* If the first byte is partial, modify the appropriate bits in it. */
         if (bit) {
                 u8 *byte = kaddr + pos;
-                while ((bit & 7) && cnt--) {
+                while ((bit & 7) && cnt) {
+                        cnt--;
                         if (value)
                                 *byte |= 1 << bit++;
                         else